Seasonal flu and COVID-19: what are the similarities? Answers from Dr. Simon-Pierre Hamadi Assane, Epidemiologist

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Extract from the article: Influenza is a highly contagious acute respiratory infectious disease caused by viruses of the genus “Influenza.” It spreads through epidemics, meaning it affects a large number of people at a given time and place. These epidemics can be global, in w

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Influenza is a highly contagious acute respiratory infectious disease caused by viruses of the genus “Influenza.” It spreads through epidemics, meaning it affects a large number of people at a given time and place. These epidemics can be global, in which case they are referred to as pandemics. The set of clinical signs of a disease is called a “syndrome,” so the set of clinical signs of influenza constitutes the “influenza syndrome.” Several diseases have symptoms characterized by influenza-like illness, including those caused by the influenza virus, SARS (Severe Acute Respiratory Syndrome), MERS (Middle East Respiratory Syndrome), and SARS Cov 2 (COVID-19).

There is therefore a strong clinical resemblance between influenza and Covid-19, which justifies influenza cases being considered as suspected Covid-19 cases, just as “headaches” could be a clinical manifestation of malaria, meningitis, high blood pressure, or other diseases. Biological analysis in the laboratory makes it possible to distinguish between the two by confirming or ruling out the suspected disease.

What is seasonal flu?

There are several types of flu: human flu, avian flu in wild or domestic birds (poultry, for example). Seasonal flu is an acute viral infection caused by an influenza virus. There are three types of seasonal flu: A, B, and C. Influenza A viruses are subdivided into subtypes based on the different types and combinations of surface proteins on the virus. Among the many subtypes of influenza A viruses, subtypes A(H1N1) and A(H3N2) are currently circulating in humans.

The circulating influenza A (H1N1) virus is also written as A (H1N1) pdm09 because it caused the 2009 pandemic and subsequently replaced the seasonal influenza A (H1N1) virus that circulated before 2009. Only influenza A viruses have caused pandemics.

Seasonal influenza, commonly known as “the flu,” occurs seasonally, as its name suggests, between November and April in the Northern Hemisphere and April to September in the Southern Hemisphere. In tropical countries such as Togo, the influenza virus circulates all year round. Several million people are affected each year in these countries. The cause is therefore viral (influenza virus). The contributing factors are much more climatic, with peaks during periods of low temperatures and dust. This is the case during the harmattan or monsoon season in our country. The flu virus is transmitted through the inhalation of droplets of saliva, spittle, or sneezes emitted by an infected person. Most initially healthy patients are contagious from the day before symptoms appear and remain so for up to five to seven days afterward. Risk factors for contracting influenza include: having a weakened immune system due to chronic stress, lack of sleep, or poor diet; frequenting public places during epidemic periods (markets, public transportation, public restrooms) and large gatherings of people (funerals, weddings, socio-cultural events).

Interview by Gamé KOKO